Commissioners unanimously agreed to hire Lawrence-based B.A. Green Construction to serve as the construction manager for the $19 million expansion of the Lawrence Public Library.

The company will serve much like a general contractor for the project, but instead of having complete leeway to hire all subcontractors for the job, the city will use a competitive bidding process to hire subcontractors for the project.

B.A. Green also will advise the city on whether it would be advantageous for the city to move the library to a temporary location while construction is under way on the expansion at Seventh and Vermont streets.

Construction on the project is expected to begin this fall.